Is ONE PIECE episode 948 filler?
Canon No, episode 948 of ONE PIECE is canon.
#948
Start Fighting Back! Luffy and the Akazaya Samurai!
反撃開始！ルフィと赤鞘の侍！
Aired 1 Nov 2020
Mochibayo compiled this list from MyAnimeList's labels, because MyAnimeList's episode data is not reaching us at the moment.